Electromagnetic relay



June 9, 1942. HANS-FREDI SCHWARTZ ET AL 2,285,467

E LECTROMAGNET I C RFLAY Filed Sept. 7, 1938 /n ve/nor': Hans-Fred! Jmu/ar/z 0((0 Baier Patented June 9, 1942 2,285,461 usc'raomoxs'rrc may Hana-Fred! Schwarts and one new, Berlin.

aasigno Aktiens rstoQLorena Gennany,

achaft Berlin-Tempelhof, L'orensweg, Germanaacomnany ApplioationSeptember V InGennany 'lClaims.

The present invention relates to electro-masnetic relays, and more specifically to the type of relays which operate in vacuum.

It is a well knownexpedient to place the contacts of an electromagnetic relay within a vacuum container in order to avoid troubles in operation which may occur on account of an oxidation of the contact elements, and to secure a nonarcing contact 'make and break even at very high potentials. Certain difliculties arise when such relays are adapted to operate at a low atmospheric pressure, for example on aircraft at great heights above the earth's surface, where flashover phenomena in the shape of spray discharges occur at high potential operation between the high voltage conducting lead-in conductors and the field 001101 the relay armature which is maintained at the earth's potential. Such troubles are attributable; at a non-uniformity in the potential 'dismbution between these elements so that the electric lines of force are subjected to such concentration at certain points that a discharge takes place.

for its object to avoid the aforesaid disadvantages, and this is carried out in accordance with the main feature of the invention by providing the vacuum vessel of such electromagnetic relays with a shielding surface which is maintained at earth's potential. This shielding may, according to a further feature of the invention, be a rim of silver applied on the inner surface of an annular torus-shaped extension of the vacuum relay.

The invention will be more readily understood from the following description taken in coniunction with the accompanying drawing, in

The invention has Wilm- Fig. l is a longitudinal section through an electromagnetic vacuum relay according to the invention, Fig. 2 is a cross section on the line 2-4 of Fig. 1, while Fig. 3 is a further cross section on the line 3-3 of Fig. l.

7, 1938, serial No. 228,756 August 13, 1937 The vacuum relay consists of a glass vessel or envelope I, an intermediate portion 2, and a closing member or cover I, on which latter the actual relay system is mounted. This system comprises, by way of an example, two rods 4 and II of insulation sealed to the cover I and these rods serve as supports for the necesmy contacts and vacuum relay.

relay is carried mote from cover a clip 0 and consists ably attached to switching elements of the The movable armature I of this from the upper end, or end re- 3, of the red I by the agency of of a hinge member 8 movinsulation, such as ceramic, for example, on which the magnetization responsive means It of the electromagnetic portion are fixed by means of member II. The contact elements II which perform a make and break of the load circuits are located adjacent to the lower end, or end near cover 3, of the armature I. The load circult or circuits are connected to the relay device partially over thelead-in conductor II at one end of the relay and this conductor is connected to thecontact element I4 and partially over leads ll sealed in the cover I at the opposite end of the envelope. One of the leads II is connected to the fixedly mounted contact element l5 and the other lead is connected to a movable contact element ii of the armature. The magnetization responsive means ill of said armature are arcuated so as to provide a small space between these means and the cooperating cores I of the relay magnet energized by windings 23 and 24.

In operation magnetic fields produced by electromagnets l6 act on the magnetization responsive members it and move the armature towards points II or it depending on the magnet energized or polarity of energization thus completing external circuits which may be connected to lead-in conductors l2 and II. The electromagnets l8 may be energized by any suitable source.

The intermediate portion 2 of the relay device carries a particular torus-shaped extension ll of annular form, the inner surface I! of which according to one feature of the invention is provided with a conductive coating of silver, for example, which may be applied by spraying or similar methods. A cylindrical member I! is soldered to the heretofore mentioned metal coating .and serves as a guide and a support for the relay device in its fitting 20 in which the cores of the relay magnet are mounted. The silver coating may in the case of need be extended along member 2 toward the glass envelope or along the envelope as so far far as approximately to the cores of the magnet. The fitting It and the cylindrical member ll of the vacuum relay are maintained at earth's potential, while the leads I! conduct high tensions. Investigations have proven that in the absence of such shielding means flashover phenomena inevitably occurs over the glass walls between the magnet coils maintained at earth's potential and the high tension conducting lead-in conductors of the vacuum relay. Such flashing-over phenomena are reliably eliminated by the provision of the metallic coating accordthe clip I and a flat strip l 01 6!! ing to the invention.

The closing member or cover 3 may, if 'desir- 3 able, be provided with a small torus-shaped annular projection ll whiohis coated with a.

layer of silver 22. This layer is then electrically connected to one of the lead-in conductors l3 oi the vacuum relay by lead It. Both lead-in conductors and this last mentioned silver coating are then maintained at the same potential when the vacuum relay is operative, so that no electric field is setup therebetween. This expedientstill more the safety against flashf-iover troubles. The connecting leads and their connecting pointsare thus rendered free of corona emu What is claimed is: 14 A vacuumtype electromagnetic relay com prising vessel member, a cover member,

andlan intermediate member rigidly jointed be- H tween said'veasel member and said cover member,.an'- armature assembly within said vessel 'member; contact means operatively associated with said armature, lead-in conductors for said contact means; at least one of said conductors extending through the cover member, magnetic means eiternal to said vessel member for operating said armature assembly, said magnetic meanisbeing spaced from said intermediate member'; arid a shield in the shape of an annular metallic coating encircling one of said members.

said cover member are made oi strongly refractory material, and said armature assembly and said contact means are mounted on said cover member.

6. A vacuum-type electromagnetic relay according to claim 1- wherein said shield is a coating of silver. a

'7. A vacuum-type electromagnetic relay according to claim 1 further comprising an annular torus-shaped extension on said intermediate member, said shield being applied to said ex-' tension.

' HANS-FREDI SCHWARTZ.

OTTO BAIER.

M e Pom na between said a extending through said cover member and said magnetic means. a, Y 

